Charged particle beam writing apparatus and charged particle beam writing method

ABSTRACT

A charged particle beam writing apparatus includes a storage unit to store writing data of a region to be written in a target object, a first dividing unit to read the writing data and divide the region to be written into at least one first data processing region that overlaps with at least a first region where a pattern has been arranged, and at least one second data processing region that overlaps with a second region where no pattern is arranged without overlapping with the first region, a data processing unit to perform data processing of predetermined data processing contents for at least one first data processing region without performing the data processing for at least one second data processing region, and a writing unit to write a pattern on the target object, based on processed data.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims the benefit of priorityfrom U.S. application Ser. No. 14/734,306, filed Jun. 9, 2015, whichclaims the benefit of priority from the prior Japanese PatentApplication No. 2014-136727 filed on Jul. 2, 2014 in Japan, and priorityfrom the prior Japanese Patent Application No. 2015-049580 filed on Mar.12, 2015 in Japan; the entire contents of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention relate generally to a chargedparticle beam writing apparatus and a charged particle beam writingmethod, and more specifically, relate to a method for achievinghigh-speed data processing in a writing apparatus.

Description of Related Art

In recent years, with high integration of LSI, the line width (criticaldimension) required for circuits of semiconductor devices is becomingprogressively narrower. As a method for forming an exposure mask (alsocalled a reticle) used to form circuit patterns on these semiconductordevices, the electron beam (EB) writing technique having excellentresolution is employed.

FIG. 15 is a conceptual diagram explaining operations of a variableshaped electron beam (EB) writing or “drawing” apparatus. The variableshaped electron beam writing apparatus operates as described below. Afirst aperture plate 410 has a quadrangular aperture 411 for shaping anelectron beam 330. A second aperture plate 420 has a variable shapeaperture 421 for shaping the electron beam 330 having passed through theaperture 411 of the first aperture plate 410 into a desired quadrangularshape. The electron beam 330 emitted from a charged particle source 430and having passed through the aperture 411 is deflected by a deflectorto pass through a part of the variable shape aperture 421 of the secondaperture plate 420, and thereby to irradiate a target object or “sample”340 placed on a stage which continuously moves in one predetermineddirection (e.g., the x direction) during writing. In other words, aquadrangular shape that can pass through both the aperture 411 of thefirst aperture plate 410 and the variable shape aperture 421 of thesecond aperture plate 420 is used for pattern writing in a writingregion of the target object 340 on the stage continuously moving in thex direction. This method of forming a given shape by letting beams passthrough both the aperture 411 of the first aperture plate 410 and thevariable shape aperture 421 of the second aperture plate 420 is referredto as a variable shaped beam (VSB) system (e.g., refer to JapanesePatent Application Laid-open No. 2008-218857).

Generally, in an electron beam writing apparatus, in order to enhancethe data processing efficiency, a writing region where patterns are tobe arranged is divided into a plurality of processing regions. Then, inthe writing apparatus, a distributed processing is carried out, namelydata processing of a pattern arranged in each processing region isperformed in parallel. For example, since the size that can be shaped byone beam shot is limited, a figure pattern defined in writing data isdivided into a plurality of shot figures each of which can be shaped byone beam shot. In that case, in shot data generation processing, ifdividing is performed so that respective processing regions may be thesame size, since densities of patterns arranged in the respectiveprocessing regions are different from each other, processing timegreatly varies depending upon the densities. Therefore, conventionally,in order to reduce the variability of the processing time, it has beencontrived to perform division so that the number of shots in eachprocessing region may be around the same (e.g., refer toJP2008-218857A).

Meanwhile, in the electron beam writing, dimensional variationrepresented by the proximity effect is corrected by adjusting anirradiation amount (dose). In that case, the corrected dose isrepresented in a dose map which has been divided into meshes.

Regarding a writing region, there is a case in which a somewhat largeregion without any pattern exists. In such a case, if dividing isperformed such that the number of shots in each divided processingregion may be around the same, the total processing region includes thelarge region without any pattern. Then, when generating shot data, sincea beam dose for forming a shot figure concerned needs to be defined, thebeam dose should be read from the dose map. If the processing region islarge, the time period to read the dose from the map is long. That is,there is accordingly a problem that the processing time for a processingregion including a region where no pattern exists is longer than thatfor a processing region which does not include a region where no patternexists.

Further, when calculating a correction coefficient (correction dose) forthe proximity effect, etc. so as to adjust a dose, calculationprocessing for obtaining an area density and calculation processing forcorrection of the proximity effect, etc. using the calculated areadensity are performed. In performing the area density calculationprocessing and the correction calculation processing, the writing regionis divided, for each processing, into a plurality of processing regions,and then, the calculation is executed for each processing region. Evenin the area density calculation processing, if dividing is alsoperformed such that the size of each processing region is the same aseach other, since densities of patterns arranged in respectiveprocessing regions are different from each other, there is greatvariability among processing time of the respective processing regions.Therefore, conventionally, dividing is performed such that the number ofshots in each processing region is around the same in order to reducethe variability of the processing time. Moreover, even in the areadensity calculation processing, if dividing is also performed such thatthe number of shots in each processing region is around the same, thetotal processing region includes a large region without any pattern. Onthe other hand, in the calculation processing for correction of theproximity effect, etc., since there is no or small amount of variabilityof the processing time which usually occurs due to various densities ofpatterns, dividing is performed so that each processing region may bethe same size. However, in the proximity effect correction calculationprocessing, it is necessary to read a calculated area density. If theprocessing region of the area density calculation processing is large,with respect to the proximity effect correction calculation processingof a processing region which even partly overlaps with the largeprocessing region of the area density calculation processing, the timeperiod to read the area density becomes long. This consequentlygenerates a problem in that the processing time for a processing regionincluding a region where no pattern exists is longer than that for aprocessing region which does not include a region where no patternexists.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the present invention, a charged particlebeam writing apparatus includes a storage unit configured to storewriting data of a region to be written in a target object, a firstdividing unit configured to read the writing data and divide the regionto be written into at least one first data processing region thatoverlaps with at least a first region where a pattern has been arranged,and at least one second data processing region that overlaps with asecond region where no pattern is arranged without overlapping with thefirst region, a data processing unit configured to perform dataprocessing of predetermined data processing contents for the at leastone first data processing region without performing the data processingfor the at least one second data processing region, and a writing unitconfigured to write a pattern on the target object, based on the dataprocessed.

According to another aspect of the present invention, a charged particlebeam writing method includes reading writing data of a region to bewritten in a target object and dividing the region to be written into atleast one first data processing region that overlaps with at least afirst region where a pattern has been arranged, and at least one seconddata processing region that overlaps with a second region where nopattern is arranged without overlapping with the first region,performing data processing of predetermined data processing contents forthe at least one first data processing region without performing thedata processing in the at least one second data processing region, andwriting a pattern on the target object, based on the data processed.

Moreover, according to another aspect of the present invention, acharged particle beam writing apparatus includes a storage unitconfigured to store writing data of a region to be written in a targetobject, a dividing unit configured to read the writing data and dividethe region to be written into a plurality of stripe regions each beingin a strip shape, a pattern existence determination unit configured todetermine, for each of the plurality of stripe regions, whether apattern is arranged in a stripe region concerned in the plurality ofstripe regions, a combining unit configured to combine successive striperegions which have been determined to be without any pattern, as oneno-pattern stripe region in the plurality of stripe regions, a dataprocessing unit configured to perform data processing of predetermineddata processing contents for stripe regions which are not combined,without performing the data processing for the no-pattern stripe region,and a writing unit configured to write a pattern on the target object,based on processed data.

Furthermore, according to another aspect of the present invention, acharged particle beam writing method includes reading writing data of aregion to be written in a target object, and dividing the region to bewritten into a plurality of stripe regions each being in a strip shape,determining, for each of the plurality of stripe regions, whether apattern is arranged in a stripe region concerned in the plurality ofstripe regions, combining successive stripe regions which have beendetermined to be without any pattern, as one no-pattern stripe region inthe plurality of stripe regions, performing data processing ofpredetermined data processing contents for stripe regions which are notcombined, without performing the data processing for the no-patternstripe region, and writing a pattern on the target object, based onprocessed data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a configuration of a writingapparatus according to a first embodiment;

FIG. 2 is a conceptual diagram for explaining each region according tothe first Embodiment;

FIG. 3 illustrates an example of a processing region according to thefirst embodiment;

FIG. 4 illustrates a division example of a processing region forgenerating shot data according to a comparative example A of the firstembodiment;

FIG. 5 illustrates a division example of a processing region forcalculating a coefficient for correcting irradiation according to thecomparative example A of the first embodiment;

FIG. 6 is a flowchart showing main steps of a writing method accordingto the first embodiment;

FIG. 7 shows a division example of a processing region for shot datageneration processing according to the first embodiment;

FIG. 8 is a schematic diagram showing an internal structure of adividing unit according to the first embodiment;

FIG. 9 is a flowchart showing internal steps of the dividing step intoDPBs (1) according to the first embodiment;

FIG. 10 is a schematic diagram describing a method of dividing into DPBsaccording to the first embodiment;

FIG. 11 shows a division example of a processing region for area densitycalculation processing and a processing region for proximity effectcorrection calculation processing according to the first embodiment;

FIG. 12 is a schematic diagram showing a configuration of a writingapparatus according to a second embodiment;

FIG. 13 is a flowchart showing main steps of a writing method accordingto the second embodiment;

FIG. 14 illustrates a combining method of stripe regions according tothe second embodiment; and

FIG. 15 is a conceptual diagram explaining operations of a variableshaped electron beam writing apparatus.

DETAILED DESCRIPTION OF THE INVENTION

In the following embodiments, there will be described an apparatus andmethod that can inhibit the prolongation of the processing time causedby a region where no pattern exists.

In the following embodiments, there will be described a configuration inwhich an electron beam is used as an example of a charged particle beam.The charged particle beam is not limited to the electron beam, and othercharged particle beam such as an ion beam may also be used. Moreover, avariable shaped beam (VSB) writing apparatus will be described as anexample of a charged particle beam apparatus.

First Embodiment

FIG. 1 is a schematic diagram showing the configuration of a writing or“drawing” apparatus according to the first embodiment. As shown in FIG.1, a writing apparatus 100 includes a writing unit 150 and a controlunit 160. The writing apparatus 100 is an example of a charged particlebeam writing apparatus, and especially, an example of a variable shapedbeam writing apparatus. The writing unit 150 includes an electronoptical column 102 and a writing chamber 103. In the electron opticalcolumn 102, there are arranged an electron gun assembly 201, anillumination lens 202, a first aperture plate 203, a projection lens204, a deflector 205, a second aperture plate 206, an objective lens207, a main deflector 208 and a sub deflector 209. In the writingchamber 103, an XY stage 105 is arranged. On the XY stage 105, there isplaced a target object or “sample” 101 such as a mask serving as awriting target substrate when writing is performed. For example, thetarget object 101 is an exposure mask used for manufacturingsemiconductor devices. The target object 101 may be, for example, a maskblank on which resist has been applied and nothing has yet been written.

The control unit 160 includes a control computer 110 (preprocessingcomputer), a memory 112, a control computer 120, a memory 122, a controlcircuit 130, and a storage devices 140, 142, 144, 146, and 148 such asmagnetic disk drives. The control computer 110, the memory 112, thecontrol computer 120, the memory 122, the control circuit 130, and thestorage devices 140, 142, 144, 146, and 148 are connected with eachother through a bus (not shown).

In the control computer 110, there are arranged a dividing unit 60 intomeshes and a shot number estimation unit 62. Functions, such as thedividing unit 60 into meshes and the shot number estimation unit 62 maybe configured by hardware such as an electric circuit, or by softwaresuch as a program causing a computer to implement these functions.Alternatively, they may be configured by a combination of hardware andsoftware. Data which is input and output to/from the dividing unit 60into meshes and the shot number estimation unit 62, and data beingoperated are stored in the memory 112 each time.

In the control computer 120, there are arranged dividing units 70, 71,72, and 74, a shot division processing unit 76, an area densitycalculation unit 78, a coefficient calculation unit 82 forproximity-effect-corrected irradiation, a dose calculation unit 84, ashot data generation unit 86, and a writing control unit 88. Thesefunctions described above may be configured by hardware such as anelectric circuit, or by software such as a program causing a computer toimplement these functions. Alternatively, they may be configured by acombination of hardware and software. Data which is input and outputto/from the dividing units 70, 71, 72, and 74, the shot divisionprocessing unit 76, the area density calculation unit 78, thecoefficient calculation unit 82 for proximity-effect-correctedirradiation, the dose calculation unit 84, the shot data generation unit86, and the writing control unit 88, and data being operated are storedin the memory 122 each time.

Writing data of the region to be written in the target object 101 isinput from the outside and stored in the storage device 140. Forexample, writing data for each stripe region to be described later isstored in the storage device 140.

FIG. 1 shows a configuration necessary for explaining the firstembodiment. Other configuration elements generally necessary for thewriting apparatus 100 may also be included. For example, although amultiple stage deflector of two stages of the main deflector 208 and thesub deflector 209 is herein used for position deflection, a single stagedeflector or a multiple stage deflector of three or more stages may alsobe used for position deflection. Input devices, such as a mouse and akeyboard, a monitoring device, an external interface circuit and thelike may be connected to the writing apparatus 100.

FIG. 2 is a conceptual diagram for explaining each region according tothe first Embodiment. As shown in FIG. 2, a writing region 10 of thetarget object 101 is virtually divided by the dividing unit 71 into aplurality of stripe regions 20 each being in a strip shape and eachhaving a width deflectable in the y direction by the main deflector 208.Further, each of the stripe regions 20 is virtually divided into aplurality of subfields (SFs) 30 (small regions) each having a sizedeflectable by the sub deflector 209. A shot FIG. 42 is to be written ata corresponding shot position in each SF 30.

FIG. 3 illustrates an example of a processing region according to thefirst embodiment. As shown in FIG. 3, the stripe region 20 is used as aunit region for writing. In the first embodiment, writing processing isperformed in each stripe region 20. Therefore, data processing is alsoperformed for each stripe region 20. In the case of FIG. 3, a certainstripe region 20 is divided into a plurality of shot number estimationmeshes 22. As to be described later, the number of shot figures in amesh is measured for each shot number estimation mesh 22 in the controlcomputer 110 in order to estimate and define the number of shots in eachshot number estimation mesh 22. FIG. 3 shows hatched shot numberestimation meshes 22 in each of which a shot figure (pattern) exists andnot-hatched shot number estimation meshes 22 in each of which no patternexists. In the case of FIG. 3, there exists no somewhat large region inwhich a pattern is not arranged, in the stripe region 20. In such acase, for example, the number of shots is counted from the writingstarting side end (e.g., the left side end in FIG. 3) of the striperegion 20, and every time the counted number exceeds a threshold value,division is performed into processing regions (DPBs). In the example ofFIG. 3, the number of shots is counted from the left end of the striperegion 20, and the position where the counted shot number exceeds thethreshold value for the first time is set as a dividing point (1)(dividing position). The region from the left end of the stripe region20 to the dividing point (1) is defined as a processing region (DPB) 1.Next, the number of shots is counted from the left end of the striperegion 20, and the position where the counted shot number exceeds twicethe threshold value is set as a dividing point (2) (dividing position).The region from the right side end (dividing point (1)) of the DPB 1 tothe dividing point (2) is defined as a DPB 2. Similarly, the number ofshots is counted from the left end of the stripe region 20, and theposition where the counted shot number exceeds three times the thresholdvalue is set as a dividing point (3) (dividing position). The regionfrom the right side end (dividing point (2)) of the DPB 2 to thedividing point (3) is defined as a DPB 3. Further, the number of shotsis counted from the left end of the stripe region 20, and if it comes tothe end of the stripe region 20 before the counted shot number exceedsfour times the threshold value, the region from the right side end(dividing point (3)) of the DPB 3 to the end of the stripe region 20 isdefined as a DPB 4. By performing dividing as described above, thestripe region 20 can be divided into a plurality of processing regionseach of which has approximately the same number of shots.

FIG. 4 illustrates a division example of a processing region forgenerating shot data according to the comparative example A of the firstembodiment. FIG. 4 shows two stripe regions, the i-th stripe region 20 aand the (i+1)th stripe region 20 b, which are adjacent to each other. Inthe example of FIG. 4, the regions (first regions) in which patternshave been arranged exist at the both ends of the stripe region 20 a, anda somewhat large region (second region) in which no pattern is arrangedexists in the central part of the stripe region 20 a. The same appliesto the stripe region 20 b. In the comparative example A, as in theconventional case, the number of shots is counted simply from the leftend of the stripe region 20 a (or stripe region 20 b), and then, theprocessing region is divided, treating the position where the countedshot number exceeds the threshold value for generating shot data as adividing point (dividing position). When the central part region inwhich no pattern exists is large, even if the number of shots is countedfrom the left end to the termination (right end) of the stripe region 20a, there is a possibility that the counted shot number does not exceedthe threshold value. In that case, as shown in FIG. 4, the entire striperegion 20 a turns out to be one processing region 450 a. Similarly, theentire stripe region 20 b turns out to be one processing region 450 b.As described above, when generating shot data, it is necessary tocalculate a beam dose for forming a shot figure concerned. Then, thedose needs to be read. Therefore, the time period to read the dosebecomes long when the processing region is large, and thus, there isaccordingly a problem that the processing time for the processing region450 a which includes the region without any pattern is longer than theprocessing time of one of the DPBs 1 to 3 or any other one of the DPBs 1to 3.

FIG. 5 illustrates a division example of a processing region forcalculating a coefficient for correcting irradiation according to thecomparative example A of the first embodiment. The case of FIG. 5 showsthree stripe regions, the i-th stripe region 20 a, the (i+1)th striperegion 20 b, and the (i−1)th stripe region 20 c, which are adjacent toeach other. In the example of FIG. 5, the regions (first regions) inwhich patterns have been arranged exist at the both ends of the striperegion 20 a, and a somewhat large region (second region) in which nopattern is arranged exists in the central part of the stripe region 20a. The same applies to the stripe regions 20 b and 20 c. In thecomparative example A, as in the conventional case, the number of shotsis counted simply from the left end of the stripe region 20 a (or striperegion 20 b or 20 c), and then, the processing region is divided,treating the position where the counted shot number exceeds thethreshold value for calculating an area density as a dividing point(dividing position). When the central part region in which no patternexists is large, even if the number of shots is counted from the leftend to the termination (right end) of the stripe region 20 a, there is apossibility that the counted shot number does not exceed the thresholdvalue. In that case, as shown in FIG. 5, the entire stripe region 20 aturns out to be one processing region 452 a. Similarly, the entirestripe region 20 b turns out to be one processing region 452 b, and theentire stripe region 20 c turns out to be one processing region 452 c.On the other hand, in the calculation processing for correction of theproximity effect, etc., since there is no or small amount of variabilityof the processing time which usually occurs due to various densities ofpatterns, dividing is performed so that each processing region may bethe same size. In such a case, as shown in FIG. 5, the stripe region 20a is divided into three processing regions 454 a, 454 b, and 454 c eachhaving the same width. The same applies to the stripe regions 20 b and20 c. In the calculation processing for correction of the proximityeffect, a calculated area density needs to be read. Therefore, forexample, when performing correction calculation for the proximity effectin the processing region 454 a, it is necessary to read data of theentire processing region 452 a which is for area density, and to extracta required area density therefrom. Accordingly, if the processing region452 a for area density is large, the time period to read an area densitybecomes long in the calculation processing for correction of theproximity effect in the processing region which even partly overlapswith the processing region for the area density calculation processing.Consequently, the processing time of the processing region for theproximity effect correction calculation becomes long. Moreover, in theprocessing region 454 b, conventionally, the proximity effect correctioncalculation has been performed though no pattern is arranged in thatregion. Therefore, the processing time for it has been needed.

Then, according to the first embodiment, dividing is performed so thatthe processing region may be divided into a region (first region) inwhich a pattern has been arranged, and a region (second region) in whichno pattern is arranged. This makes it possible to avoid that the wholeof the region without any pattern, whose width is wider than apredetermined size, is included in one processing region (DPB).

FIG. 6 is a flowchart showing main steps of a writing method accordingto the first embodiment. As shown in FIG. 6, the writing method of thefirst embodiment executes a series of steps: a dividing step (S102) intomeshes, a shot number estimation step (S104), a dividing step (S110)into DPBs (1), a dividing step (S112) into shots, a dividing step (S120)into DPBs (2), an area density calculation step (S122), a dividing step(S130) into DPBs (3), a coefficient calculation step (S132) forproximity-effect-corrected irradiation, a dose calculation step (S134)(irradiation time calculation step), a shot data generation step (S140),and a writing step (S142). The dividing step (S102) into meshes and theshot number estimation step (S104) are executed as preprocessing beforestarting writing processing.

In the dividing step (S102) into meshes, the dividing unit 60 intomeshes (second dividing unit) divides the region to be written in thetarget object 101 into a plurality of mesh regions of a predeterminedsize. For example, each stripe region 20 is divided into a plurality ofmesh regions, which is performed for estimating the number of shots.Therefore, for each stripe region 20, the stripe region 20 concerned isdivided into a plurality of shot number estimation meshes 22. The sizeof the shot number estimation mesh 22 may be set appropriately on acase-by-case basis. For example, it is preferable for the size to be 1/nof the division width (short side size) of the stripe region 20. Forexample, preferably, it is about 1/10 to 1/20. Alternatively, dividingis performed by the same size as the subfield 30 shown in FIG. 2.

In the shot number estimation step (S104), the shot number estimationunit 62 reads writing data from the storage device 140, and assigns, foreach shot number estimation mesh 22, a figure pattern which is to bearranged in the shot number estimation mesh 22 concerned. The figurepattern assigned to each shot number estimation mesh 22 is divided intoshot figures. For example, the figure pattern may be divided, by apreset maximum shot size, into figures such as a quadrangle or anisosceles right triangle which can be shaped by the writing apparatuses100. Then, the number of divided shot figures is counted, and the numberof shot figures, i.e., the number of shots, for each shot numberestimation mesh 22 is estimated. By using each estimated number of shotsas a map value of a corresponding shot number estimation mesh 22, a shotnumber map is generated. The shot number map is stored in the storagedevice 142.

In the dividing step (S110) into DPBs (1), the dividing unit 70 (firstdividing unit) reads writing data from the storage device 140, anddivides a region to be written, such as the stripe region 20, into aplurality of data processing regions (DPBs) (1). Here, the processingregion (DPB) (1) for dividing processing into shots (shot datageneration processing) is formed.

FIG. 7 shows a division example of a processing region for shot datageneration processing according to the first embodiment. As shown inFIG. 7, according to the first embodiment, the dividing unit 70 dividesa region to be written, such as the stripe region 20, into dataprocessing regions 50 a and 50 c (first data processing regions) thatrespectively overlap with at least the regions 24 a and 24 b (firstregions) in each of which a pattern has been arranged, and a dataprocessing region 50 b (second data processing region) that overlapswith the region 26 (second region) in which no pattern is arranged,without overlapping with the regions 24 a and 24 b where patterns arearranged. In the case of FIG. 7, at both the ends of the stripe region20, there are aligned shot number estimation meshes 22 (meshes which arehatched) whose numbers of shots are not zero (that is, a pattern hasbeen arranged therein). On the other hand, in the central part of thestripe region 20, there are aligned, in a large range, shot numberestimation meshes 22 (meshes which are not hatched) each of whose numberof shots is zero (that is, a pattern has not been arranged). In thatcase, according to the first embodiment, the data processing region 50 ais formed at the position overlapping with at least the region 24 a andincluding, as a margin, the shot number estimation meshes 22 of one or afew columns arrayed in the x direction (or “rows” arrayed in the ydirection in FIG. 7) at the region 26 side close to the region 24 a.Moreover, the data processing region 50 c is formed at the positionoverlapping with at least the region 24 b and including, as a margin,the shot number estimation meshes 22 of one or a few columns at theregion 26 side close to the region 24 b. Further, the data processingregion 50 b which does not overlap with the regions 24 a and 24 b butoverlaps with the region 26 is formed.

Although the example of FIG. 7 shows the case where the regions 24 withpatterns exist at both the ends of the stripe region 20, it is notlimited thereto. For example, there is a possibility that the region 24with a pattern exists only at one end. Moreover, there is a possibilitythat the region 24 with a pattern exists only in the central part of thestripe region 20. Alternatively, a plurality of regions 24 with patternsand regions 26 without any pattern may exist in a mixed manner. Thus,the dividing unit 70 divides a region to be written into at least onedata processing region 50 a which overlaps with at least the region 24(first region: region with a pattern) where a pattern has been arranged,and at least one data processing region 50 b which overlaps with theregion 26 (second region: region without any pattern) where no patternis arranged, without overlapping with the region 24.

FIG. 8 is a schematic diagram showing the internal structure of adividing unit according to the first embodiment. As shown in FIG. 8, thedividing unit 70 includes an input unit 90, a determination unit 91, acolumn total shot number (Sum column) calculation unit 92, determinationunits 93, 94, 95, and 96, a threshold value (th) calculation unit 97, asum total shot number (Sum) calculation unit 98, a determination unit99, a dividing processing unit 172, and an addition unit 174. Thesefunctions described above may be configured by hardware such as anelectric circuit, or by software such as a program causing a computer toimplement these functions. Alternatively, they may be configured by acombination of hardware and software. Data which is input and outputto/from the input unit 90, the determination unit 91, the column totalshot number (Sum column) calculation unit 92, the determination units93, 94, 95, and 96, the threshold value (th) calculation unit 97, thesum total shot number (Sum) calculation unit 98, the determination unit99, the dividing processing unit 172, and the addition unit 174, anddata being operated are stored in the memory 122 each time. Althoughherein the dividing unit 70 of FIG. 1 is shown, each of the dividingunits 72 and 74 has the same internal structure as that of the dividingunit 70.

FIG. 9 is a flowchart showing internal steps of the dividing step intoDPBs (1) according to the first embodiment. In FIG. 9, the dividing step(S110) into DPBs (1) executes a series of steps as internal steps: aninput step (S202), a determination step (S204), a k-th column total shotnumber calculation step (S206), determination steps (S208), (S210), and(S212), a threshold value calculation step (S214), a dividing processingstep (S216), an addition step (S218), a sum total shot numbercalculation step (S219), determination steps (S220) and (S222), and athreshold value calculation step (S224). Although the dividing step(S110) into DPBs (1) of FIG. 6 is herein shown, each of the dividingstep (S120) into DPBs (2) and the dividing step (S130) into DPBs (3)executes the same internal steps as those of the dividing step (S110)into DPBs (1).

FIG. 10 is a schematic diagram describing a method of dividing into DPBsaccording to the first embodiment. The example of FIG. 10 shows the casewhere the total number of shots in the region 24 a does not exceed athreshold value th which is for dividing the processing region.

In the input step (S202), the input unit 90 inputs writing data (stripedata) of the stripe region 20 concerned from the storage device 140.Moreover, the input unit 90 inputs a shot number map in which the numberof shots estimated for each shot number estimation mesh 22 is definedfrom storage device 142.

The k-th column in the x direction from the left end of the striperegion 20 concerned in the shot number estimation meshes 22 is definedas the k-th shot number estimation mesh 22 column. For each shot numberestimation mesh 22 column, n shot number estimation meshes 22 have beenformed in the y direction in the dividing step (S102) into meshes.

When starting the dividing step (S110) into DPBs (1), 1 is set as aninitial value of k, and 0 is set as an initial value of a sum total shotnumber Sum. Moreover, the threshold value th (threshold value fordividing processing into shots) of the number of shots to be used whendividing the stripe region 20 into at least one processing region is setin advance. Moreover, a column value m for setting a margin (margincolumn value) (value for dividing processing into shots) is also set inadvance.

In the determination step (S204), the determination unit 91 determineswhether a column number k of the shot number estimation mesh 22 columnof the stripe region 20 which is a target to be determined is largerthan the last column kmax. When the column number k is larger than thelast column kmax, it returns to the input step (S202), and inputs thenext stripe data. When the column number k is not larger than the lastcolumn kmax, it proceeds to the k-th column total shot numbercalculation step (S206).

In the k-th column total shot number calculation step (S206), the columntotal shot number (Sum column) calculation unit 92 calculates a k-thcolumn total shot number (Sum column) that serves as a sum total valueof the number of shots defined for the k-th shot number estimation mesh22 column which is the k-th column in the x direction from the left endof the stripe region 20 to be determined.

In the determination step (S208), the determination unit 93 determineswhether the calculated k-th column total shot number (Sum column) iszero. In the example of FIG. 10, in the case of k=1, since there are twoshot number estimation meshes 22, for each of which the number of shotsbeing not 0 is defined, in the first mesh column 22, it is determinedthat Sum column is not zero. For example, in the case of k=4, since ashot number estimation mesh 22 for which the number of shots being not 0is defined and a shot number estimation mesh 22 for which the number ofshots being 0 is defined are mixed in the fourth mesh column 22, it isdetermined that Sum column is not zero. On the other hand, in the casesof k=6 to 23, since there are two shot number estimation meshes 22, foreach of which the number of shots being 0 is defined, in each of thesixth to twenty-third mesh columns 22, it is determined that Sum columnis zero. When Sum column is zero, it proceeds to the determination step(S210). When Sum column is not zero, it proceeds to the sum total shotnumber calculation step (S219).

In the determination step (S210), the determination unit 94 determineswhether every Sum column of from the (k−(m−1))th column to the (k−1)thcolumn is zero. Now, there will be described a case where the margincolumn value m is set as m=4. In the example of FIG. 10, with respect tok=6, no Sum column is zero in the third to fifth mesh 22 columns. Withrespect to k=7, although no Sum column is zero in the fourth and fifthmesh 22 columns, Sum column is zero in the sixth mesh 22 column. Withrespect to k=9, every Sum column is zero in the sixth to eighth mesh 22columns. Similarly, with respect to k=10 to 23, every Sum column is zeroin the (k−(m−1))th column to the (k−1)th column. When any Sum column offrom the (k−(m−1))th column to the (k−1)th column is not zero, itproceeds to the addition step (S218). When every Sum column of from the(k−(m−1))th column to the (k−1)th column is zero, it proceeds to thedetermination step (S212).

In the determination step (S212), the determination unit 95 determineswhether Sum column of the (k-m)th column is zero or not zero. In theexample of FIG. 10, if m=4, with respect to k=9, Sum column is not zeroin the fifth mesh 22 column. On the other hand, with respect to k=10 to23, Sum column is zero in the (k−m)th column. When Sum column of the(k−m)th column is not zero, it proceeds to the threshold valuecalculation step (S214). When Sum column of the (k−m)th column is zero,it proceeds to the addition step (S218).

In the threshold value calculation step (S214), the threshold value (th)calculation unit 97 calculates a new threshold value (th) by adding apreset threshold value th to the sum total shot number Sum. At thispoint, since the sum total shot number Sum has not been updated yet, thesum total shot number Sum is still the initial value 0. Therefore, thethreshold value (th) after calculation is, at this point, the presetthreshold value th.

In the dividing processing step (S216), the dividing processing unit 172divides the processing region while regarding the end point of the k-thmesh 22 column with respect to which Sum column of the (k−m)th column isnot zero in the determination step (S212), as a dividing point (1),wherein the end point is the boundary between the k-th column and the(k+1)th column. Thereby, the first processing region DPB 1 is formed bythe mesh 22 columns from the first column to the k-th column withrespect to which Sum column of the (k−m)th column is not zero in thedetermination step (S212). In the example of FIG. 10, if m=4, DPB 1 isformed by the mesh 22 columns from the first column to the ninth column.After the dividing processing, it proceeds to the addition step (S218).

In the addition step (S218), the addition unit 174 adds 1 to the currentset kin order to obtain a new k. By this processing, the mesh 22 columnadvances successively from 1 in the stripe region 20. Then, the dividingunit 70 successively performs dividing the stripe region 20 to bewritten, advancing in the x direction (predetermined dividingdirection). Then, as described above, when a column k of interest (thatis, a target column k, or column k concerned) goes into the region 26(second region) without pattern from the pattern region 24 a (firstregion) with pattern, the dividing unit 70 sets a dividing position (1)in the region 26 without any pattern such that DPB 1 (first dataprocessing region) is formed partly overlapping with the region 26without pattern.

In the sum total shot number calculation step (S219), the sum total shotnumber (Sum) calculation unit 98 adds Sum column of the k-th mesh 22column to the current sum total shot number (Sum).

In the determination step (S220), when Sum column of the k-th column isnot zero in the determination step (S208) described above, thedetermination unit 96 determines whether every Sum column of from the(k−m)th column to the (k−1)th column is zero. In the case of FIG. 10, ifm is set to be m=4, for example, with respect to k=24, every Sum columnis zero in the mesh 22 columns from the twentieth column to thetwenty-third column. With respect to k=25, although every Sum column iszero in the mesh 22 columns from the twenty-first column to thetwenty-third column, Sum column is not zero in the twenty-fourth mesh 22column. When every Sum column is zero in the (k−m)th column to the(k−1)th column, it proceeds to the threshold value calculation step(S214). If one of Sum columns is not zero in the (k−m)th column to the(k−1)th column, it proceeds to the determination step (S222).

In the threshold value calculation step (S214), the threshold value (th)calculation unit 97 calculates a new threshold value (th) by adding apreset threshold value th to the current sum total shot number Sum. Atthis point, since the sum total shot number Sum has not been updatedyet, the sum total shot number Sum is still the initial value 0.Therefore, the threshold value (th) after calculation is, at this point,the preset threshold value th.

In the dividing processing step (S216), the dividing processing unit 172divides the processing region while regarding the start point of thek-th mesh 22 column with respect to which every Sum column of the(k−m)th column to the (k−1)th column is zero in the determination step(S220), as a dividing point (2), wherein the start point is the boundarybetween the (k−1)th column and the k-th column. Thereby, the secondprocessing region DPB 2 is formed by the mesh 22 columns from the columnof the dividing point (1) to the k-th column with respect to which everySum column of the (k−m)th column to the (k−1)th column is zero in thedetermination step (S220). In the example of FIG. 10, if m=4, DPB 2 isformed by mesh 22 columns from the tenth column to the nineteenthcolumn. After the dividing processing, it proceeds to the addition step(S218).

As described above, when the column k of interest goes into the region24 b (first region) with pattern from the region 26 (second region)without pattern, the dividing unit 70 sets a dividing position (2) inthe region 26 without pattern such that DPB 2 (second data processingregion) which overlaps with the region 26 without pattern, withoutoverlapping with the regions 24 a and 24 b (first region) each with apattern is formed. Consequently, this leads to that when the column k ofinterest goes into the region 24 b (first region) with pattern from theregion 26 (second region) without pattern, the dividing unit 70 sets adividing position (2) in the region 26 without pattern such that DPB 3(first data processing region) which partly overlaps with the region 26without pattern is formed.

Then, when the column k advances in the stripe region 20, it comes tothe k-th mesh 22 column with respect to which no Sum columns of the(k−m)th column to the (k−1)th column are zero in the determination step(S219). In the example of FIG. 10, with respect to k=25, not all Sumcolumns of the (k−m)th column to the (k−1)th column are zero. Therefore,it proceeds to the determination step (S222).

In the determination step (S222), the determination unit 99 determineswhether the current sum total shot number (Sum) having been set exceedsthe threshold value th. When not exceeded, it proceeds to the additionstep (S218). When exceeded, it proceeds to the threshold valuecalculation step (S224). In the example of FIG. 10, since the sum totalshot number (Sum) does not exceed the threshold value th after thedividing position (2) to the end of the stripe region 20, DPB 3 (firstdata processing region) is formed by the mesh 22 columns of from thedividing position (2) to the end of the stripe region 20. In addition,although not shown, if there is a dense pattern part in the region 24 bwith a pattern, or if the width of the region 24 b with a pattern islong, the current sum total shot number (Sum) having been set may exceedthe threshold value th.

In the threshold value calculation step (S224), the threshold value (th)calculation unit 97 calculates anew threshold value by adding a presetthreshold value th having been set in advance to the current setthreshold value th.

In the dividing processing step (S216), the dividing processing unit 172divides the processing region while regarding the end point of the k-thmesh 22 column with respect to which the current sum total shot number(Sum) has exceeded the threshold value th in the determination step(S222), as an unshown dividing point (3), wherein the end point is theboundary between the k-th column and the (k+1)th column. The newthreshold value th calculated in the threshold value calculation step(S224) is to be used for a next unshown dividing point (4).

Although the example of FIG. 10 shows the case where the total of thenumbers of shots in the region 24 a with a pattern does not exceed thethreshold value th, it is not limited thereto. There may be a case wherethe total of the numbers of shots exceeds the threshold value th. Inthat case, when no Sum columns of the (k−m)th column to the (k−1)thcolumn are zero in the determination step (S219) and the current sumtotal shot number (Sum) exceeds the threshold value th in thedetermination step (S222), dividing the processing region should beperformed regarding the endpoint of the k-th mesh 22 column, as anunshown dividing point, wherein the end point is the boundary betweenthe k-th column and the (k+1)th column.

Moreover, if dividing the processing region is performed while thenumber of shots exceeds the threshold value th in the region 24 a with apattern, the current sum total shot number Sum will be, when it proceedsto the threshold value calculation step (S214), the value that wascalculated in the sum total shot number calculation step (S219).

As described above, when dividing the stripe region 20 (region to bewritten) is performed so that DPBs 1 and 3 (first data processingregion) each partly overlapping with the region 26 (second region)without pattern may be formed, the dividing unit 70 sets dividingpositions (1) and (2) in the region 26 without pattern such that m mesh22 columns (predetermined margin width), located from each internal endpoint of the regions 24 a and 24 b (first region) with patterns towardinside the region 26 without pattern, are included in the DPBs.

As described above, the stripe region 20 (for example, region to bewritten) is divided into a plurality of meshes 22 each of which issmaller than a data processing region (first and second data processingregions). Then, the dividing unit 70 performs dividing, using theestimated number of shots, into DBPs 1 and 3 (first data processingregion) and DBP 2 (second data processing region). In that case, DBPs 1and 3 (first data processing region) include both the mesh region wherethe estimated number of shots is not zero and the mesh region where theestimated number of shots is zero. On the other hand, DBP 2 (second dataprocessing region) includes the mesh region where the estimated numberof shots is zero, and excludes the mesh region where the estimatednumber of shots is not zero.

As described above, according to the first embodiment, basically, everytime it has become the threshold value th, the processing region isdivided such that the number of shots may be around the same as eachother. Further, when the region 26 without pattern is formed composed ofcolumns exceeding twice the margin column value m, the processing regionis divided by the method described above regardless of the number ofshots.

In the dividing step (S112) into shots, the shot division processingunit 76 performs processing of dividing into shots for each processingregion which was divided in the dividing step (S110) into DPBs (1).Specifically, the shot division processing unit 76 reads writing datafrom the storage device 140, and assigns, for each processing region, afigure pattern to be located in the processing region concerned from thewriting data. Then, for each processing region, the assigned figurepattern is divided into a plurality of shot figures each being the sizeirradiatable by one beam shot. For example, a figure pattern is divided,in the x direction from its one end, by a preset maximum shot size.Then, a remained part of the figure pattern, which was not able to bedivided by the maximum shot size, and a part of the figure pattern,which is equivalent to the maximum shot size, are added to be dividedinto halves. Thereby, the figure pattern is divided into a plurality offigures each being the maximum shot size, and two shot figures eachbeing not extremely smaller than the maximum shot size. A similardivision is to be performed with respect to the y direction.

The shot division processing unit 76 (an example of a data processingunit) does not perform data processing of the shot division processing(predetermined data processing contents) in the data processing region50 b (second data processing region) which overlaps with the region 26(second region) without pattern, and performs data processing of theshot division processing (predetermined data processing contents) in thedata processing regions 50 a and 50 c (first data processing region)which respectively overlap with at least the regions 24 a and 24 b(first region) with a pattern. Thus, it is possible to avoid to performcalculation processing in the data processing region 50 b for which thecalculation is unnecessary, thereby aiming at an effective use of theresource. Eventually, it leads to shortening of the processing timeconcerning the entire processing region.

In the dividing step (S120) into DPBs (2), the dividing unit 72 readswriting data from the storage device 140, and divides a region to bewritten, such as the stripe region 20, into a plurality of dataprocessing regions (DPB) (2). In this case, the processing region (DPB)(2) for area density calculation processing is formed. The dividingprocessing method of the dividing step (S120) into DPBs (2) may be thesame as that of the dividing step (S110) into DPBs (1) except that thethreshold value th and the margin column value m are different fromthose of the dividing step (S110).

FIG. 11 shows a division example of the processing region for areadensity calculation processing and the processing region for proximityeffect correction calculation processing according to the firstembodiment. As shown in FIG. 11, according to the first embodiment, thedividing unit 72 divides a region to be written, such as the striperegion 20, into data processing regions 52 a and 52 c (first dataprocessing regions) that respectively overlap with at least the regions24 a and 24 b (first regions) in each of which a pattern has beenarranged, and a data processing region 52 b (second data processingregion) that overlaps with the region 26 (second region) in which nopattern is arranged, without overlapping with the regions 24 a and 24 bwhere patterns are arranged. In the case of FIG. 11, at the both ends ofthe stripe region 20, there are aligned shot number estimation meshes 22(meshes which are hatched) whose numbers of shots are not zero (that is,a pattern has been arranged therein). On the other hand, in the centralpart of the stripe region 20, there are aligned, in a large range, shotnumber estimation meshes 22 (meshes which are not hatched) each of whosenumber of shots is zero (that is, a pattern has not been arranged). Inthat case, according to the first embodiment, the data processing region52 a is formed at the position overlapping with at least the region 24 aand including, as a margin, the shot number estimation meshes 22 of oneor a few columns at the region 26 side close to the region 24 a.Moreover, the data processing region 52 c is formed at the positionoverlapping with at least the region 24 b and including, as a margin,the shot number estimation meshes 22 of one or a few columns at theregion 26 side close to the region 24 b. Further, the data processingregion 52 b which does not overlap with the regions 24 a and 24 b butoverlaps with the region 26 is formed. The case of FIG. 11 shows threestripe regions, the (i−1)th stripe region, the i-th stripe region, andthe (i+1)th stripe region, which are adjacent to each other. In each ofthe three stripe regions 20, the regions 24 a and 24 b with patternsexist at both the ends of the stripe region 20, and the region 26without pattern exists in the central part of the stripe region 20.

Although the example of FIG. 11 shows the case where the regions 24 withpatterns exist at both the ends of the stripe region 20, it is notlimited thereto. For example, there is a possibility that the region 24with a pattern exists only at one end. Moreover, there is a possibilitythat the region 24 with a pattern exists only in the central part of thestripe region 20. Alternatively, a plurality of regions 24 with patternsand regions 26 without any pattern may exist in a mixed manner. Thus,the dividing unit 72 divides a region to be written into at least onedata processing region 52 a which overlaps with at least the region 24(first region: region with a pattern) where a pattern has been arranged,and at least one data processing region 52 b which overlaps with theregion 26 (second region: region without any pattern) where no patternis arranged, without overlapping with the region 24.

In the area density calculation step (S122), the area densitycalculation unit 78 performs calculation processing for obtaining anarea density ρ(x) for each processing region (DPB) (2) divided by thedividing step (S120) into DPBs (2). Specifically, the area densitycalculation unit 78 reads writing data from the storage device 140, andassigns, for each processing region (DPB) (2), a figure pattern to belocated in the processing region concerned from the writing data. On theother hand, the stripe region 20 is divided into a plurality of meshregions of a predetermined size. For example, it is preferable for themesh size to be about 1/10 of the influence radius of the proximityeffect, and specifically, to be about 0.5 to 2 μm, for example. In eachprocessing region (DPB) (2), for each mesh region located in theprocessing region, an area density ρ(x) of a figure pattern arranged inthe mesh region is calculated. Here, the position x denotes a vector.

The area density calculation unit 78 (an example of the data processingunit) does not perform data processing of the area density calculationprocessing (predetermined data processing contents) in the dataprocessing region 52 b (second data processing region) which overlapswith the region 26 (second region) where no pattern is arranged. On theother hand, the area density calculation unit 78 performs dataprocessing of the area density calculation processing (predetermineddata processing contents) in the data processing regions 52 a and 52 c(first data processing regions) which respectively overlap with at leastthe regions 24 a and 24 b (first regions) in which patterns have beenarranged. Thus, it is possible to avoid to perform calculationprocessing in the data processing region 52 b for which the calculationis unnecessary, thereby aiming at an effective use of the resource.Eventually, it leads to shortening of the processing time concerning theentire processing region. The area density calculation unit 78generates, for each processing region 52, an area density ρ(x) map usinga calculated area density p as a map value of each mesh. The generatedarea density ρ map is stored in the storage device 144. Moreover, here,a proximity effect density U(x) used for proximity effect correctioncalculation may also be calculated. The proximity effect density U(x) iscalculated, for each processing region 52, as a value obtained byconvolving a distribution function g_(p) (x) and an area density ρ(x).Then, the generated proximity effect density U(x) map is to be stored inthe storage device 144.

In the dividing step (S130) into DPBs (3), the dividing unit 74 dividesa region to be written such as the stripe region 20 into a plurality ofdata processing regions (DPB) (3), for example. In this case, aprocessing region (DPB) (3) for proximity effect correction calculationprocessing is formed. Since the processing time of proximity effectcorrection calculation processing is affected by the area, but notaffected by pattern densities, or is ignorable as described above, theprocessing region is divided into a plurality of processing regions 54a, 54 b, and 54 c being the same size as each other, as shown in FIG.11, for example. The example of FIG. 11 shows the processing regions 54a, 54 b, and 54 c only for the i-th stripe region 20.

In the coefficient calculation step (S132) forproximity-effect-corrected irradiation (proximity effect correctioncalculation processing), the coefficient calculation unit 82 forproximity-effect-corrected irradiation calculates, for each processingregion (DPB) (3), a proximity effect correction irradiation coefficientD_(p)(x) for correcting a dimension variation resulted from theproximity effect. An unknown proximity effect correction irradiationcoefficient D_(p)(x) can be obtained by solving the following equation(1), using a proximity effect coefficient η, a distribution functiong_(p)(x), and an area density ρ(x).

$\begin{matrix}{{\frac{D_{p}(x)}{2} + {\eta {\int{{D_{p}\left( x^{\prime} \right)}{g_{p}\left( {x - x^{\prime}} \right)}{\rho \left( x^{\prime} \right)}{dx}^{\prime}}}}} = {\frac{1}{2} + \eta}} & (1)\end{matrix}$

Here, when calculating the proximity effect correction irradiationcoefficient D_(p)(x), the area density ρ(x) map of the processing region(DPB) (2) which at least partly overlaps with a target processing region(DPB) (3) is read.

In the example of FIG. 11, although area density ρ(x) maps for theprocessing regions 52 a and 52 b are to be read in the processing region54 a, since the area density ρ(x) map for the processing region 52 bdoes not exist, it is sufficient to read the area density ρ(x) map forthe processing region 52 a. Similarly, although area density ρ(x) mapsfor the processing regions 52 c and 52 b are to be read in theprocessing region 54 c, since the area density ρ(x) map for theprocessing region 52 b does not exist, it is sufficient to read the areadensity ρ(x) map for the processing region 52 c. Furthermore, since theprocessing region 54 b overlaps only with the processing region 52 b ofthe region 26 without pattern, the calculation (proximity effectcorrection calculation) itself of the proximity effect correctionirradiation coefficient D_(p)(x) can be omitted from the beginning inthe processing region 54 b.

As described above, if the processing region for area densitycalculation concerning the processing region 54 b in proximitycorrection calculation is only the processing region 52 b that overlapswith the region 26 without pattern, without overlapping with the regions24 a and 24 b with patterns, the calculation (proximity effectcorrection calculation) itself of the proximity effect correctionirradiation coefficient D_(p)(x) can be omitted. Consequently, it ispossible to shorten the processing time.

In the dose calculation step (S134) (irradiation time calculation step),the dose calculation unit 84 calculates a dose D(x) by using a base doseD_(B) and a calculated proximity effect correction irradiationcoefficient D_(p)(x). The dose D(x) can be defined by the followingequation (3).

D(x)=D _(B)(x)·D _(p)(x)  (3)

Although the proximity effect correction has been described herein as anexample, dose adjustment correction is not limited thereto. In additionto the proximity effect correction, fogging correction, loading effectcorrection, etc. may also simultaneously be performed, for example. Thedose calculation unit 84 generates a dose D(x) map concerning the striperegion 20 or the writing region 10, for example, by using a calculateddose D(x) as a map value of each mesh for area density calculation, forexample. The generated dose D (x) map is stored in the storage device146. Moreover, since the dose D (x) is adjusted by a beam irradiationtime t(x), it is also preferable to generate an irradiation time t(x)map by calculating an irradiation time t(x) by dividing the dose D(x) bya current density J of an electron beam.

In the shot data generation step (S140), for each processing region(DPB) (1) for shot data generation processing, the shot data generationunit 86 partially cuts out the dose D(x) map (or irradiation time t(x)map), to be corresponding to the processing region (DPB) (1) concerned.Then, the shot data generation unit 86 reads in (loads) the cut-out doseD(x) maps (or irradiation time t(x) maps) in order, reads out(retrieves) data of a dose (or irradiation time) for each shot figure,and additionally defines it in the shot data. The generated shot data isstored in the storage device 148.

In such a case, if the size of the processing region (DPB) (1) is large,the cut-out dose D(x) map (or irradiation time t(x) map) is also large.Therefore, it takes time to read data of a dose (or irradiation time).According to the first embodiment, by dint of forming the processingregion 50 b that overlaps with the region 26 in which no pattern isarranged, without overlapping with the regions 24 a and 24 b in whichpatterns are arranged, the cut-out the dose D(x) map (or irradiationtime t(x) map) can be reduced by the size of the processing region 50 b.Therefore, processing time for reading out data of a dose (orirradiation time) can be shortened.

In the writing step (S142), under the direction of the writing controlunit 88, the control circuit 130 reads shot data and controls the driveof the writing unit 150. Thereby, the writing unit 150 writes a patternon the target object 101 based on processed data. The writing unit 150writes a figure pattern defined by the writing data on the target object100, using the electron beam 200. Specifically, it operates as describedbelow.

The electron beam 200 emitted from the electron gun 201 (emission unit)irradiates the entire first aperture plate 203 having a quadrangularopening by the illumination lens 202. At this point, the electron beam200 is shaped to be a quadrangle. Then, after passing through the firstaperture plate 203, the electron beam 200 of a first aperture image isprojected onto the second aperture plate 206 by the projection lens 204.The first aperture image on the second aperture plate 206 isdeflection-controlled by the deflector 205 so as to change the shape andsize of the beam to be variably shaped. After passing through the secondaperture plate 206, the electron beam 200 of a second aperture image isfocused by the objective lens 207 and deflected by the main deflector208 and the sub deflector 209 so as to reach a desired position on thetarget object 101 placed on the XY stage 105 which moves continuously.FIG. 1 shows the case of using multiple stage deflection of two stagesof the main and sub deflectors for position deflection. In such a case,the electron beam 200 of a shot concerned should be deflected to areference position in a subfield (SF), which is obtained by furthervirtually dividing the stripe region, by the main deflector 208 whilefollowing the movement of the stage, and the beam of a shot concernedshould be deflected to each irradiation position in the SF by the subdeflector 209. Moreover, the dose D(x) should be controlled by anirradiation time of the electron beam 200.

As described above, according to the first embodiment, prolongation ofthe processing time caused by a region where no pattern exists can beinhibited. Therefore, high-speed shot generation processing can beachieved. Moreover, dose correction processing, such as unnecessaryproximity effect correction calculation processing, etc. can be omitted.

Second Embodiment

According to the first embodiment, dividing is performed for each striperegion 20 so that the processing region of the stripe region 20concerned may be divided into a processing region in which a pattern hasbeen arranged, and a processing region in which no pattern is arranged.Now, according to the second embodiment, there will be described a casewhere the writing region 10 is divided into the stripe region 20 inwhich a pattern has been arranged, and the stripe region 20 in which nopattern is arranged.

FIG. 12 is a schematic diagram showing the configuration of a writingapparatus according to the second embodiment. FIG. 12 is the same asFIG. 1 except that a determination unit 73 and a combining unit 75 areadded in the control computer 120. Functions, such as the dividing units70, 71, 72, and 74, the determination unit 73, the combining unit 75,the shot division processing unit 76, the area density calculation unit78, the coefficient calculation unit 82 for proximity-effect-correctedirradiation, the dose calculation unit 84, the shot data generation unit86, and the writing control unit 88 may be configured by hardware suchas an electric circuit, or by software such as a program causing acomputer to implement these functions. Alternatively, they may beconfigured by a combination of hardware and software. Data which isinput and output to/from the dividing units 70, 71, 72, and 74, thedetermination unit 73, the combining unit 75, the shot divisionprocessing unit 76, the area density calculation unit 78, thecoefficient calculation unit 82 for proximity-effect-correctedirradiation, the dose calculation unit 84, the shot data generation unit86, and the writing control unit 88, and data being operated are storedin the memory 122 each time.

FIG. 13 is a flowchart showing main steps of a writing method accordingto the second embodiment. The writing method of FIG. 13 according to thesecond embodiment is the same as that of FIG. 6 except that a dividingstep (S106) into stripes, a pattern existence determination step (S107),and a stripe combination step (S108) are added after the shot numberestimation step (S104) and before the dividing step (S110) into DPBs(1), the dividing step (S120) into DPBs (2) and the dividing step (S130)into DPBs (3). The contents of the present embodiment are the same asthose of the first embodiment except what is described below.

The contents of the dividing step (S102) into meshes and the shot numberestimation step (S104) are the same as those of the first embodiment.

In the dividing step (S106) into stripes, the dividing unit 71 readswriting data from the storage device 140, and divides the writing region10 (an example of a region to be written) into a plurality ofstrip-shaped stripe regions 20 as shown in FIG. 2.

In the pattern existence determination step (S107), the determinationunit 73 (pattern existence determination unit) determines, for each of aplurality of stripe regions 20, whether a pattern is arranged in thestripe region concerned. Specifically, the determination unit 73 reads ashot number map generated for each stripe region from the storage device142, and distinguishes the stripe region 20 in which the number of shotsis zero from the stripe region 20 in which the number of shots is one ormore.

FIG. 14 illustrates a combining method of stripe regions according tothe second embodiment. FIG. 14 shows stripe regions 20 a to 20 i, as anexample. In these stripe regions 20 a to 20 i, the stripe regions 20 a,20 b, 20 h, and 20 i which are hatched denote stripe regions (striperegions with patterns) in each of which a pattern has been arranged, andthe stripe regions 20 c, 20 d, 20 e, 20 f, and 20 g denote striperegions (stripe regions without any pattern) in each of which no patternis arranged.

In the stripe combination step (S108), the combining unit 75 combinessuccessive stripe regions (stripe regions 20 d, 20 e, and 20 f) whichhave been determined to be without any pattern in a plurality of striperegions 20, as a no-pattern stripe region 21. However, as stripe regionsin each of which no pattern is arranged, the stripe regions 20 c and 20g also exist. It is preferable that the stripe regions 20 c and 20 g,which are before and after the no-pattern stripe region 21, are notcombined in order to be margin regions.

In the dividing step (S110) into DPBs (1), the dividing step (S120) intoDPBs (2), and the dividing step (S130) into DPBs (3), data processing isnot performed for the no-pattern stripe region 21, but performed forstripe regions 20 other than the no-pattern stripe region 21. In otherwords, the dividing units 70, 72, and 74, the shot division processingunit 76, the area density calculation unit 78, the coefficientcalculation unit 82 for proximity-effect-corrected irradiation, the dosecalculation unit 84, and the shot data generation unit 86 (an example ofthe data processing unit) perform data processing of their respectivecontents for the stripe regions 20 which are not combined, withoutperforming the data processing for the no-pattern stripe region 21.Thereby, it is possible to omit the determination itself to determinethat processing for a certain DPB is unnecessary though thedetermination has conventionally been performed as a result of DPBprocessing executed in parallel to writing or of related DPB processing.

In the writing step (S142), under the direction of the writing controlunit 88, the control circuit 130 reads shot data and controls the driveof the writing unit 150. Thereby, the writing unit 150 writes a patternon the target object 101 based on processed data. The writing unit 150writes a figure pattern defined by the writing data on the target object100, using the electron beam 200. The other contents are the same asthose of the first embodiment.

As described above, according to the second embodiment, prolongation ofthe processing time caused by a stripe region 20 where no pattern existscan be inhibited. Therefore, high-speed shot generation processing canbe achieved more than the first embodiment. Furthermore, dose correctionprocessing, such as unnecessary proximity effect correction calculationprocessing, etc. can be further omitted compared to the firstembodiment.

The embodiments have been explained referring to concrete examplesdescribed above. However, the present invention is not limited to thesespecific examples. For example, although the dividing step (S106) intostripes described in FIG. 13 is omitted in FIG. 6, it should beunderstood that the dividing step (S106) into stripes is also performedin the first embodiment. Moreover, the shot number map described abovemay be generated for each stripe region 20 as a unit, or for eachwriting region 10 (or chip region) as a unit by performing mergeprocessing of the entire writing region 10 (or chip region).

While the apparatus configuration, control method, and the like notdirectly necessary for explaining the present invention are notdescribed, some or all of them can be selectively used case-by-casebasis. For example, although description of the configuration of thecontrol unit for controlling the writing apparatus 100 is omitted, itshould be understood that some or all of the configuration of thecontrol unit can be selected and used appropriately when necessary.

In addition, any other charged particle beam writing apparatus andcharged particle beam writing method that include elements of thepresent invention and that can be appropriately modified by thoseskilled in the art are included within the scope of the presentinvention.

Additional advantages and modification will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A charged particle beam writing apparatus comprising: a storage device configured to store writing data of a region to be written in a target object; processing circuitry configured perform functions of a dividing section that reads the writing data and divide the region to be written into a plurality of stripe regions each being in a strip shape; a pattern existence determination section that determines, for each of the plurality of stripe regions, whether a pattern is arranged in a stripe region concerned in the plurality of stripe regions; and a data processing section that performs data processing of predetermined data processing contents for stripe regions which have been determined to be with any pattern, without performing the data processing for a stripe region which have been determined to be without any pattern, in the plurality of stripe regions; and a writing mechanism including a stage on which the target object is placed, a charged particle beam source, and a deflector and configured to write a pattern on the target object, based on processed data.
 2. The apparatus according to claim 1, wherein the processing circuitry is further configured perform function of a combining section that combines successive stripe regions which have been determined to be without any pattern, as one no-pattern stripe region in the plurality of stripe regions, wherein the data processing section performs data processing of predetermined data processing contents for stripe regions which are not combined, without performing the data processing for the no-pattern stripe region.
 3. A charged particle beam writing method comprising: reading writing data of a region to be written in a target object, and dividing the region to be written into a plurality of stripe regions each being in a strip shape; determining, for each of the plurality of stripe regions, whether a pattern is arranged in a stripe region concerned in the plurality of stripe regions; performing data processing of predetermined data processing contents for stripe regions which have been determined to be with any pattern, without performing the data processing for a stripe region which have been determined to be without any pattern, in the plurality of stripe regions; and writing a pattern on the target object, based on processed data.
 4. The method according to claim 3, further comprising: combining successive stripe regions which have been determined to be without any pattern, as one no-pattern stripe region in the plurality of stripe regions, wherein when performing the data processing of predetermined data processing contents, data processing of predetermined data processing contents for stripe regions which are not combined is performed without performing the data processing for the no-pattern stripe region. 